diff --git a/lua/gitsigns/attach.lua b/lua/gitsigns/attach.lua
index 4bbc8cbe..f8dad72f 100644
--- a/lua/gitsigns/attach.lua
+++ b/lua/gitsigns/attach.lua
@@ -362,7 +362,7 @@ local attach_throttled = throttle_by_id(function(cbuf, ctx, aucmd)
   })
 
   -- Initial update
-  manager.update(cbuf, cache[cbuf])
+  manager.update(cbuf)
 end)
 
 --- Detach Gitsigns from all buffers it is attached to.
diff --git a/lua/gitsigns/cache.lua b/lua/gitsigns/cache.lua
index f9790df3..8dc2433d 100644
--- a/lua/gitsigns/cache.lua
+++ b/lua/gitsigns/cache.lua
@@ -41,10 +41,6 @@ function CacheEntry:get_compare_rev(base)
   return string.format(':%d', stage)
 end
 
-function CacheEntry:get_staged_compare_rev()
-  return self.commit and string.format('%s^', self.commit) or 'HEAD'
-end
-
 function CacheEntry:get_rev_bufname(rev)
   rev = rev or self:get_compare_rev()
   return string.format('gitsigns://%s/%s:%s', self.git_obj.repo.gitdir, rev, self.git_obj.relpath)
diff --git a/lua/gitsigns/debounce.lua b/lua/gitsigns/debounce.lua
index 1699f1ca..f0d5c3cc 100644
--- a/lua/gitsigns/debounce.lua
+++ b/lua/gitsigns/debounce.lua
@@ -7,39 +7,31 @@ local M = {}
 --- @generic F: function
 --- @param ms number Timeout in ms
 --- @param fn F Function to debounce
+--- @param hash? integer|fun(...): any Function that determines id from arguments to fn
 --- @return F Debounced function.
-function M.debounce_trailing(ms, fn)
-  local timer = assert(uv.new_timer())
+function M.debounce_trailing(ms, fn, hash)
+  local running = {} --- @type table<any,uv.uv_timer_t>
+  if type(hash) == 'number' then
+    local hash_i = hash
+    hash = function(...)
+      return select(hash_i, ...)
+    end
+  end
   return function(...)
+    local id = hash and hash(...) or true
+    if running[id] == nil then
+      running[id] = assert(uv.new_timer())
+    end
+    local timer = running[id]
     local argv = { ... }
     timer:start(ms, 0, function()
       timer:stop()
-      fn(unpack(argv))
+      running[id] = nil
+      fn(unpack(argv, 1, table.maxn(argv)))
     end)
   end
 end
 
---- Throttles a function on the leading edge.
----
---- @generic F: function
---- @param ms number Timeout in ms
---- @param fn F Function to throttle
---- @return F throttled function.
-function M.throttle_leading(ms, fn)
-  local timer = assert(uv.new_timer())
-  local running = false
-  return function(...)
-    if not running then
-      timer:start(ms, 0, function()
-        running = false
-        timer:stop()
-      end)
-      running = true
-      fn(...)
-    end
-  end
-end
-
 --- Throttles a function using the first argument as an ID
 ---
 --- If function is already running then the function will be scheduled to run
diff --git a/lua/gitsigns/manager.lua b/lua/gitsigns/manager.lua
index 6a23ad9c..f72eb5e5 100644
--- a/lua/gitsigns/manager.lua
+++ b/lua/gitsigns/manager.lua
@@ -12,7 +12,6 @@ local throttle_by_id = require('gitsigns.debounce').throttle_by_id
 local log = require('gitsigns.debug.log')
 local dprint = log.dprint
 local dprintf = log.dprintf
-local eprint = log.eprint
 
 local subprocess = require('gitsigns.subprocess')
 local util = require('gitsigns.util')
@@ -63,12 +62,13 @@ end
 --- @param top integer
 --- @param bot integer
 --- @param clear boolean
---- @param untracked boolean
-local function apply_win_signs(bufnr, top, bot, clear, untracked)
+local function apply_win_signs(bufnr, top, bot, clear)
   local bcache = cache[bufnr]
   if not bcache then
     return
   end
+
+  local untracked = bcache.git_obj.object_name == nil
   apply_win_signs0(bufnr, signs_normal, bcache.hunks, top, bot, clear, untracked)
   if signs_staged then
     apply_win_signs0(bufnr, signs_staged, bcache.hunks_staged, top, bot, clear, false)
@@ -106,7 +106,7 @@ function M.on_lines(buf, first, last_orig, last_new)
     end
   end
 
-  M.update_debounced(buf, cache[buf])
+  M.update_debounced(buf)
 end
 
 local ns = api.nvim_create_namespace('gitsigns')
@@ -394,6 +394,24 @@ local function update_show_deleted(bufnr)
   end
 end
 
+--- @param bufnr? integer
+--- @param cb function
+M.buf_check = async.wrap(function(bufnr, cb)
+  vim.schedule(function()
+    if bufnr then
+      if not api.nvim_buf_is_valid(bufnr) then
+        dprint('Buffer not valid, aborting')
+        return
+      end
+      if not cache[bufnr] then
+        dprint('Has detached, aborting')
+        return
+      end
+    end
+    cb()
+  end)
+end, 2)
+
 local update_cnt = 0
 
 --- Ensure updates cannot be interleaved.
@@ -401,38 +419,36 @@ local update_cnt = 0
 --- whilst another one is in progress. If this happens then schedule another
 --- update after the current one has completed.
 --- @param bufnr integer
---- @param bcache? Gitsigns.CacheEntry
-M.update = throttle_by_id(function(bufnr, bcache)
+M.update = throttle_by_id(function(bufnr)
   local __FUNC__ = 'update'
-  bcache = bcache or cache[bufnr]
-  if not bcache then
-    eprint('Cache for buffer ' .. bufnr .. ' was nil')
-    return
-  end
+  M.buf_check(bufnr)
+  local bcache = cache[bufnr]
   local old_hunks, old_hunks_staged = bcache.hunks, bcache.hunks_staged
   bcache.hunks, bcache.hunks_staged = nil, nil
 
-  async.scheduler_if_buf_valid(bufnr)
-  local buftext = util.buf_lines(bufnr)
   local git_obj = bcache.git_obj
 
   if not bcache.compare_text or config._refresh_staged_on_update then
     bcache.compare_text = git_obj:get_show_text(bcache:get_compare_rev())
-    async.scheduler_if_buf_valid(bufnr)
+    M.buf_check(bufnr)
   end
 
+  local buftext = util.buf_lines(bufnr)
+
   bcache.hunks = run_diff(bcache.compare_text, buftext)
+  M.buf_check(bufnr)
 
   if config._signs_staged_enable then
     if not bcache.compare_text_head or config._refresh_staged_on_update then
-      bcache.compare_text_head = git_obj:get_show_text(bcache:get_staged_compare_rev())
+      local staged_compare_rev = bcache.commit and string.format('%s^', bcache.commit) or 'HEAD'
+      bcache.compare_text_head = git_obj:get_show_text(staged_compare_rev)
+      M.buf_check(bufnr)
     end
     local hunks_head = run_diff(bcache.compare_text_head, buftext)
+    M.buf_check(bufnr)
     bcache.hunks_staged = gs_hunks.filter_common(hunks_head, bcache.hunks)
   end
 
-  async.scheduler_if_buf_valid(bufnr)
-
   -- Note the decoration provider may have invalidated bcache.hunks at this
   -- point
   if
@@ -442,7 +458,7 @@ M.update = throttle_by_id(function(bufnr, bcache)
   then
     -- Apply signs to the window. Other signs will be added by the decoration
     -- provider as they are drawn.
-    apply_win_signs(bufnr, vim.fn.line('w0'), vim.fn.line('w$'), true, git_obj.object_name == nil)
+    apply_win_signs(bufnr, vim.fn.line('w0'), vim.fn.line('w$'), true)
 
     update_show_deleted(bufnr)
     bcache.force_next_update = false
@@ -497,9 +513,7 @@ local function on_win(_cb, _winid, bufnr, topline, botline_guess)
   end
   local botline = math.min(botline_guess, api.nvim_buf_line_count(bufnr))
 
-  local untracked = bcache.git_obj.object_name == nil
-
-  apply_win_signs(bufnr, topline + 1, botline + 1, false, untracked)
+  apply_win_signs(bufnr, topline + 1, botline + 1, false)
 
   if not (config.word_diff and config.diff_opts.internal) then
     return false
diff --git a/lua/gitsigns/watcher.lua b/lua/gitsigns/watcher.lua
index 56f7979d..64087d59 100644
--- a/lua/gitsigns/watcher.lua
+++ b/lua/gitsigns/watcher.lua
@@ -9,28 +9,13 @@ local util = require('gitsigns.util')
 local cache = require('gitsigns.cache').cache
 local config = require('gitsigns.config').config
 local debounce_trailing = require('gitsigns.debounce').debounce_trailing
+local manager = require('gitsigns.manager')
+
+local buf_check = manager.buf_check
 
 local dprint = log.dprint
 local dprintf = log.dprintf
 
---- @param bufnr? integer
---- @param cb function
-local buf_check = async.wrap(function(bufnr, cb)
-  vim.schedule(function()
-    if bufnr then
-      if not api.nvim_buf_is_valid(bufnr) then
-        dprint('Buffer not valid, aborting')
-        return
-      end
-      if not cache[bufnr] then
-        dprint('Has detached, aborting')
-        return
-      end
-    end
-    cb()
-  end)
-end, 2)
-
 --- @param bufnr integer
 --- @param old_relpath string
 local function handle_moved(bufnr, old_relpath)
@@ -74,7 +59,9 @@ local function handle_moved(bufnr, old_relpath)
   dprintf('%s buffer %d from %s to %s', msg, bufnr, old_name, bcache.file)
 end
 
-local watch_gitdir_handler = async.void(function(bufnr)
+--- @param bufnr integer
+local handler = debounce_trailing(200, async.void(function(bufnr)
+  local __FUNC__ = 'watcher_handler'
   buf_check(bufnr)
 
   local git_obj = cache[bufnr].git_obj
@@ -100,8 +87,8 @@ local watch_gitdir_handler = async.void(function(bufnr)
 
   cache[bufnr]:invalidate()
 
-  require('gitsigns.manager').update(bufnr, cache[bufnr])
-end)
+  require('gitsigns.manager').update(bufnr)
+end), 1)
 
 -- vim.inspect but on one line
 --- @param x any
@@ -112,14 +99,15 @@ end
 
 local M = {}
 
+local WATCH_IGNORE = {
+  ORIG_HEAD = true,
+  FETCH_HEAD = true
+}
+
 --- @param bufnr integer
 --- @param gitdir string
 --- @return uv.uv_fs_event_t
 function M.watch_gitdir(bufnr, gitdir)
-  -- Setup debounce as we create the luv object so the debounce is independent
-  -- to each watcher
-  local watch_gitdir_handler_db = debounce_trailing(200, watch_gitdir_handler)
-
   dprintf('Watching git dir')
   local w = assert(uv.new_fs_event())
   w:start(gitdir, {}, function(err, filename, events)
@@ -134,14 +122,14 @@ function M.watch_gitdir(bufnr, gitdir)
     -- The luv docs say filename is passed as a string but it has been observed
     -- to sometimes be nil.
     --    https://github.com/lewis6991/gitsigns.nvim/issues/848
-    if filename == nil or vim.endswith(filename, '.lock') then
+    if filename == nil or WATCH_IGNORE[filename] or vim.endswith(filename, '.lock') then
       dprintf('%s (ignoring)', info)
       return
     end
 
     dprint(info)
 
-    watch_gitdir_handler_db(bufnr)
+    handler(bufnr)
   end)
   return w
 end